Maven JXR project (formally Java Cross Reference) is a library to analyze a set of Java source files and produces documentation in HTML format à la Javadoc.
Take a look at this JXR report to see an example.
The original JXR code was merged in 2004 with the Javasrc project from the defunct Jakarta Alexandria project. The code was first maintained within the Maven 1 JXR plugin. In September 2005, it was voted to fork the base and create a separate library.
The following example shows how to use Maven JXR in more advanced use cases: